In a large bowl, combine the cracker crumbs, pecans, sugar and butter; set aside 1/3 cup for topping. Press remaining crumb mixture onto the bottom and 1 inch up the sides of a greased 9-inch springform pan.
Place springform pan on a double thickness of heavy duty foil (about 18 inches square). Securely wrap foil around pan.
In a large bowl, beat cream cheese and sugar until smooth. Beat in the sour cream, vanilla and butter flavoring. Add eggs, beat on low speed just until combined. Fold in pecans. Pour into crust, sprinkle with reserved crumb mixture. Place springform pan in a large baking pan; add 1 inch of hot water to larger pan.
Bake in a preheated 325º oven for 70-80 minutes or until center is almost set. Remove springform pan from water bath. Cool on a wire rack for 10 minutes. Carefully run a knife around edge of pan to loosen; cool 1 hour longer. Refrigerate overnight. Remove sides of pan.